Patent GB-672961-A (GB)
Title: Improved machine for folding sheet material into bellows
IPC: B31F1/00
Filed: 1949-11-02
Abstract: 672,961. Pleating sheet material. GENERAL MOTORS CORPORATION. Nov. 2, 1949 [Nov. 4, 1948], No. 28036/49. Class 141. [Also in Group XVI] A machine for folding sheet material in tubular form into bellows form comprises a plurality of series of folding blades which are movable simultaneously longitudinally and inwardly of the tube. During a folding operation a tubular blank of sheet material 148, Fig. 1, is secured at one end between a clamping cylinder 134 and a clamping plate 84 secured to a support, while the other end fits over a cylindrical bush 152 secured to a stop 154 carried by a bracket 156. The bracket 156, Fig. 8, is secured to one plate 89 of a pair of plates 88, 89 forming a movable carriage supported on rollers 92 and 93 running between a pair of bevelled rails 34. A handle 115 attached to a shaft 114 serves to rotate a gear 112 mounted on the shaft 114 and in mesh with a rack 102 such that the carriage may be moved along the rails in either direction. Pairs of L-shaped folding-blades 54 and 55 are secured to pins 51 and 50 respectively, the blades 54 being slidable in slots in the pins 50 and the blades 55 being slidable in slots in the pins 51. The pins 50 and 51 connect inner and outer links 43 and 42 of a lazy tongs linkage supported by alternate centre pins 46 carrying rollers 37 movable between the rails 34 and by longer pins 48 positioned in alternate central apertures of links 42, 43. Similarly, pairs of folding blades 74 and 75 are secured to pins 71 and 70 respectively, the blades 74 being slidable in slots in the pins 70 and the blades 75 being slidable in slots in the pins 71. The pins 70 and 71 connect inner and outer links 61 and 60 of a second lazy tongs linkage supported by alternate pivot pins 64 carrying bevelled blocks 66 slidable between a pair of rails 16. Intermediate pins 68 extend through central holes in the links 60 and 61 and project between the rails 16 for sliding engagement therewith. The pins 70 and 71 are in alignment with pins 46 and 48 of the first lazy tongs, the pins 48 having slotted ends 76 which engage the lower edges of folding blades 74; similarly the pins 68 have slotted ends 77 for the folding blades 55. Thus the two lazy tongs are interlocked to maintain equal spacing between each of the sets of folding blades. The folding blades 54, 55 at the left hand end of the machine as seen in Fig. 1, are held in a longitudinally fixed position by reason of a slot between a U-shaped guide 80 and the support 21 which limits the movement of the pins 50 and 51. The corresponding end of the second lazy tongs is fixed by the end pin 66 engaging a bore in the machine frame. When the carriage comprising the plates 88 and 89 is moved by the handle 115 towards the left hand end of the machine, Fig. 1, with a blank 148 secured in position for folding, both sets of lazy tongs are collapsed, thus causing the blades 54 and 55 to move downwardly and upwardly respectively to form a pair of horizontal folds in the blank; similarly the blades 74 and 75 are moved horizontally to form a pair of vertical folds. The lazy tongs comprising the links 42 and 43 are collapsed by reason of two end links being connected to the carriage by a bolt 90 carrying the roller 92, while the second lazy tongs is collapsed by an arm 116 connected to the carriage plate 89, the arm 116 having a slot which guides the pins 70 and 71 connected to the end pair of links 60 and 61. A blower 120, Fig. 2, supplies compressed air to an electric heater during folding so that heated compressed air is supplied to the interior of the tubular blank through a conduit 124. The compressed air serves to support the tubular blank while, in the case of resin-impregnated paper, the heat increases the flexibility of the paper. When the bellows is folded the carriage is returned to open the blades and a handle 146 is moved upwardly to permit the clamping sleeve 134 to move under spring pressure longitudinally away from the plate 84, Fig. 1, through the action of a rotatable cam 132 to unclamp the blank. The folding blades 54 and 55 are then moved away from the blades 74 and 75 by moving the support 21, and a similar support 22 which carry the rails 34, transversely of the machine along guides 11 and 12 thus allowing removal of the bellows.